Derived Scores and the Normal Curve Peabody Picture Vocabulary Test
A z-score indicates how many standard deviation units an examinee is from the mean of the group. For example, if an examinee has a z-score of -1.00, he or she is one standard deviation below the mean. See the guidelines in Exercises 13 and 14 to review the meanings of percentile ranks and stanines. Note that the standard scores in this excerpt are expressed on the same scale as IQ scores. See Exercise 15 to review the meaning ofiQ scores.